Self-contained engine hand-tool.



W. G. SHELTON.

SELF CONTAINED EN GINE HAND TOOL. APPLICATION FILED mm. 11, 1913.

1,201,363., Patented Oct. 17,1916.

INVENTOR WITN'ESSES: w

30 I By Aftorneyx,

UNITED sTA rEs WILLIAM GENTRY SHELTON, OF NEW YORK, N. Y.

SELF-CON'.l'.AI1\l'11D ENGINE HAND-TOOL.

Specification of Letters Patent.

Application filed March 17, 1913. Serial No. 754,918.

To all whom it may concern:

Be it known that 1, WILLIAM GENTRY S nL'roN, a citizen of the UnitedStates, residing in the borough of Manhattan, city, county, and State ofNew York, have invented, certain new and useful Improvements in Self-Contained Engine Hand- Tools, of which the following is a specification.

Among the objects of the invention is the provision of a drill stock orhand-piece carrying a self-contained engine, the handpiece and enginebeing in the form of and constituting a hand-tool. The invention alsocomprises controlling means carried by the hand tool for thetransmission mechanism 4 between the engine shaft and the drivenspindle, and for the motor.

The rotary parts of a motor which is carried by a hand tool requiringthe most delicate and precise manipulations must be small for lightnessand rotated at a high speed for power, too high indeed for directapplication to certain tools, for instance a dental drill or alliedtool. The ability to effectively reduce the speed and increase the powerat the point of utilization was a problem the solving of which made theuse of this form of tool feasible. x

In the drawings accompanying this specification one practicableembodiment of a form of the invention is illustrated, where-- Figure 1is a view partly in cent'ral, longitudinal or axial section and partlyin elevation; Fig. 2 is a section taken on the plane at about the line2-2 of Fig. 1 looking down. (The section upon which Fig. 1 is taken isillustrated in this view by the line 1-1). Fig. 3 is a view partly inelevation and partly in section substantially transverse to the sectionof.Fig. 1. The plane of this section is illustrated at the line 3-3 inFig. 2. .Fig. 4 is a transverse section taken on a plane at about theline 4-4 of Fig. 1 looking up. Fig. 5 is a detail of the switch andcontact mechanism. Fig. 6 is a diagram of the wiring.

The drill stock or part 7 carrying the driven shaft 13 in theillustration is a commercial form of dental hand piece and car-,

ries a dental engine, the-whole comprising a hand tool having aself-contained engine. The hand tool illustrated has the usual couplingscrew 8 to which is attached the casing of the engine. In the presentillustration the coupling 8 is connected with a coupling member 9. Thecoupling member 9 has a flange. 10 for engaging the member 11 of thehand-piece for holding this in position relatively to the coupling 8. Inthis form of handpiece the chuck 12 of the drivenshaft 13 is closed bymoving the hand-piece away from the coupling 8 and is opened by movingit toward the same.

The main portion 14 of the engine casing is shown having ascrew-threaded connection with the coupling 9. This main portionconstitutes a frame as well as the housing of the engine. The engine inthe present instance is driven by means of an electric motor. The motorwhich is employed is a single bearing motor which has been found mosteflicient for steadiness as well as'lightness. The field magnets 15together with their coils 16 are mounted on this member 14. A bearing 17in the form of a tube or Patented 001.47, 1916. I

hollow cylinder is secured at one end, the

18 which has a spindle or shaft 19 extend-- ing through the bearing 17and also a bearing 20 for engaging the outer surface of the bearing 17.A motor of suflicient lightness for use in a hand tool to get therequisite power will have to run at a too high rate of speed for drivingcertain tools. It is therefore necessary to gear the speed down betweenthe motor or engine shaft 19 and the driven shaft 13. The transmissionconnection for effecting this reduction "in the present illustrationcomprises a roller gearing. A member 21 having an external bearingsurface is shown mounted upon the engine shaft 19. Outside this is amember 22 having an internal bearing surface, and between these membersis a race of balls 23 carried by a ball cage 24. The ball cage carries aseries of pins 25, three in the present illustration, and the drivenshaft 13 carries a coupling for such pins, in the present instance adisk 26 having a series of notches 27 for receiving and engaging thepins 25. When the member 21 is rotated, and the member 22 is free .torotate, it will rotate tation of the member 21, and the ball cageremains substantially stationary. Upon ina reverse direction to thedirection of roeither slowing down or stopping the rotation of themember 22 the ball cage will be rotatedv in the direction of rotation ofthe member 21 but at a reduced speed, the reduction being about 2% to 1in the present showing. A brake or friction member 28 is provided forthis purpose, and is carried by a resilient arm 29 which is mounted uponthe hand piece, in such position that the operator may readily engage itby his fingers when he desires to rotate the driven shaft 13 andwhatever tool 30 .he may be employing in the chuck;

The engine casing not only comprises the members above referred to but acover member 31 for the main frame member 14. This cover member isoscillatorily mounted upon the bolts 32 which extend from the framemember 14 through the field magnets and through slots 33 in the covermember 31. These slots are for the purpose of limiting the amount ofoscillation of the member 31. This member is also provided with a flange34 surrounding the-free end of the frame member 14 for making a securejoint between these parts and guiding the oscillation of the member 31.The purpose of such oscillation is for changing the position of thebrushes and switches for effecting a re ersal of rotation. of thearmature.

The circuit is substantially as follows: The lead line 35 comes into thecasing with the lead line 36 in the form ofa cable, the lead line 35passes around the field coils 37 and 38, and then has two contactbuttons 39, 40; the lead line 36 has two contact buttons 41 and 42. Apair of buttons 43 and 44 are associated with the brushes 45 and 46respectively, which run upon the armature 47.

When it is desired to drive the armature in one direction the cap member31 of the engine casing will be moved to the position to bring the partsas illustrated in Figs. 5 and 6, wherein the contact button 43 is inengagement with the contactbutton 41 and the contact button 44 will bein engagement with the contact button 40. When, however, it is desiredto reverse the direction of the armature and thereby reverse thedirection of the tool, the operator may, while still holding the tool inoperative position, move the cover member 31 to its other limit of tureand also of the tool 3.0. The buttons J movement and bring the button 43into engagement with the button 39, and the button 44 into engagementwith the button 42, thereby changing the direction of current and thedirection of rotation of the armaconnected with the lead lines are shownmounted upon insulation bridges 48, which are held in position upon thebolts 32.

From the foregoing description it will be apparent that drills and othertools may be readily inserted in and removed from the chuck upon thedriven shaft, as occasion may demand, and that the reductiontransmission gearing will reduce the speed transmitted to these tools toa safe working speed, and this without undue vibration. It will also beapparent that the tool may be stopped and started without stopping andstarting the motor, and that the tool may be 1 ing the use of the tooland While the transmission connection is in efficient or workingposition or when these are at rest as oocasion may demand,

- The reduction transmission in the illustration is connected to thedriven shaft and located at one end of the hand piece and the chuck onsuch shaft is located at the opposite end of the hand piece. This is ofparticular advantage. in a mechanically controlled clutch. V

In the illustration the power is shown applied to the inner of the threemembers of the clutch and taken from the intermediate member, althoughthe power may be applied to any one ofthe three members andtaken fromeither of. the others. I

- In the construction described the use of the particular form oftransmission gearing is of importance for several, reasons. In .order tobring the tool within the compass of weight which is permissible, anextremely small and rapidly rotating motor must be provided, and in suchconstructions toothed reduction gearing is unsuitable for the purpose.Furthermore, the gearing herein provided is subject to quick and easycontrol by the finger of the usergmoved in a normal direction. It willbe'understood, however, that the gearing set forth is capable of otherusesthan that to which it is shown as applied, and is adapted to belocated at other points than that disclosed. v

While but one embodiment of'the invention has been shown for the purposeof illustrating the same, yet it will be apparent that motor, anelectric switch carried by the cas-- mg for controlling the'current tothe motor,

and a controlling member for said coupling means carried by thehand-piece whereby the motor and shaft may be instantaneously uncoupledat will for coupling the shaft to the moto-r'and uncouplingthe sametherefrom.

2. In a self-contained engine hand-tool,

the combination with a casing, of a hand .piece carried thereby,a drivenshaft in the rotation of the driven shaft.

i. In a self-contained engine hand-tool, the combination with a casing,of a hand piece carried thereby, a driven shaft in the hand'piece, anelectric motor in the casing, transmission mechanism between the motorshaft and the driven shaft, and a finger piece fast with the hand pieceand extending into the casing for controlling the trans missionmechanism, and means for controlling the current to the motor.

5. The combination with a hand piece anda driven shaft mounted therein,of a motor, a casing forthe motor having one part carried by the handpiece and carrying the motor, and another part oscillator-ii) mounted onthe other part, and means controlled by the oscillation of such part forcontrolling the direction of rotation of the mot-or, and

a controlling member carried by the hand piece for coupling the shaft tothe motor and uncoupling the same therefrom 6. The combination with ahand piece and a driven shaft mounted therein, of a motor,

a casing for the motor having one part carried by the hand piece andcarrying the motor, and another part-'oscillatorily mounted on the otherpart and carrying the brushes for the motor, the oscillation of suchpart serving to control the direction of rotation of the motor, and acontrolling member carried by the hand piece for coupling the shaft tothe motor and uncoupling the same therefrom.

7. The combination with a hand piece, of a driven shaft carried thereby,a chuck on the shaft at one end of the hand piece and a reductiontransmission and clutch on the shaft at the other end of the hand piece,and an actuator for the clutch carriedby the said I hand piece.

8. The combination with a hand piece, of a driven shaft carried thereby,a chuck carried by the shaft at one end of the hand piece and a memberof a transmission mech anism connected to the shaft at the other end ofthe hand piece, and an actuator for the transmission mechanism carriedby the hand piece.

In witness whereof, I have hereunto signed my name in the presence oftwo subscribing witnesses.

WVILLIAM GENTRY SHELTON. W'itnesses CHAS. LYON RUssELL. Ti-imms F.TVALLAGI-I.

